warn_about_nonfunctional_selection Subroutine

  subroutine warn_about_nonfunctional_selection(diagnostic_switch, name)
    use run_parameters, only: use_old_diagnostics
    use mp, only: proc0
    !> Diagnostic switch
    logical, intent(in) :: diagnostic_switch
    !> Name of the switch
    character(len=*), intent(in) :: name

    character(len=3) :: diagnostics_module

    if (use_old_diagnostics) then
      diagnostics_module = "old"
    else
      diagnostics_module = "new"
    end if

    if (diagnostic_switch .and. proc0) then
      write(*, '(a, a, a, a, a)') "WARNING: diagnostic '", name, &
           "' is (currently) non-functional in ", diagnostics_module, &
           " diagnostics module. This will have no effect."
    end if
  end subroutine warn_about_nonfunctional_selection